Continued dissapointment w/A700 Flash exposure

[alphaman07]

David and fellow members of Photoclubalpha:

This is my first post on this forum. I have been a participant of the Sony SLR Forum of DPReview.com since 2007 as MinoltaMan78, and I continue to participate in that forum. I valued greatly DK's insights on that forum and thought DPReview acted atrociously in banning him permanently. But, thankfully, there is this site to continue to cherish DK's insights on Sony/Minolta cameras.

I would appreciate David especially to weigh in on the fact that after six months of owning the A700, I remain dissatisfied with the tendency of the camera to underexpose flash shots when there is white in the scene. I like to do lots of candid flash photography in my church, which has white walls everywhere. I posted a recent example of this happening on DPReview according to the following link:

http://forums.dpreview.com/forums/read. ... e=29765992

For the examples shown here, I used that 5600HS-D flash, A-mode, ADI flash exposure, and CZ16-80 lens.

Would use of the 58AM flash (which I am considering buying) fix this problem?

I am considering buying my wife a digital SLR for her birthday next month, and she is favoring a Nikon. Next Sabbath in church, I hope to do a side-by-side flash exposure experiment with a church friend's Nikon D300 and SB-600 flash.

Any new insights on this issue?

Thanks!

Fred from Pittsburgh, PA, USA

[David Kilpatrick]

Welcome Fred. Hope Pittsburgh is not as wet and cold as Scotland is at this time of year, but I suspect it is having been there once!

If you are using ADI exposure and have an ADI lens like the 16-80, the camera should not underexpose. Your 1/3rd flash compensation is a trivial figure, given that the depth of your subject requires about a two to three stop overall variation in exposure! Really, the exposure is correct, but your scene is so deep that the back wall etc ends up too dark.

Here's how to get that shot absolutely perfect:

Set the camera to Night Portrait mode (I know it is not night, but trust me on this - set the mode dial to Night Portrait)
Set DRO+2
Set ISO 400

Do nothing further apart from just shooting. You'll find the rebalanced ambient plus flash exposure, and the DRO+2, makes a perfect shot from these conditions.

David

[Javelin]

what I've found is that the flash will expose correctly when it's set to auto. in the case of my 36am the green auto light is on.. In the night shot mode it is on. and I notice it does seem to expose better. I was just trying some shots, I tried your method and the slow (rear) sync method but the ambient is way too dark and the shutter is too slow. I got an awesome double exposure effect on one shot of my daughter but thats not what was intended. the trouble m thought I had a handle on is the same as Fred's. but in testing it again tonight I guess I'm not so sure I understand it again. Can you comment on using the flash in the more manual modes ?

[David Kilpatrick]

In auto modes, the camera will attempt to balance daylight/existing light and the flash when set to Fill Flash mode which is the default. You will get shutter speed from 1/60 to 1/160th selected by the metering, and an aperture which is often very close to wide open on program. If you use something like A mode and stop down to f/11, for example, at ISO 100, many room scenes will always be underexposed. In Night Portrait mode the shutter opening time has more freedom so 1/30, 1/20 or even longer times (in dark environments) are possible. You should use a fast enough ISO speed to avoid speeds like 1/4 which can produce ghosting or double exposures.

DRO+2 or +3 only works to full efficiency with multi zone metering enabled, but this can cause occasional serious underexposure problems with flash (if a reflective item happens to hit a metering cell and focus point). That's why it is useful to fix on centre focus point AF, not wide zone, when using flash.

Don't overestimate the power of flash.Typical on-camera bounce is a normal domestic room calls for ISO 400 at an aperture of f4 for subjects like the example shown - a small room and a single subject, maybe f5.6. A large room like a classroom or hall, and you can't bounce at all - it doesn't work unless you are using ISO 1600 at f2.8 or something equally extreme, on the 36AM. Get any conditions other than a perfect white ceiling (say a wooden ceiling) and you can add one stop to normal flash shots, anything up to three stops to bounce shots.

This is why wedding photographs don't use bounce or direct flash, and hardly ever use auto flash. They use full power flash every time, with a diffuser like the Gary Fong Whale Tale, and they simply get to learn that a group shot is f5.6, a couple is f8, a close up portrait is f11 and so on (of course it's the distance which matters, not the subject, but they learn very fast how to set the camera manually).

David

[Javelin]

I'm just going to have to isolate myself in a room with the flash and fight it out untill I know intuitivly how the flash is going to act. The nightshot giving the extra freedome for shutter speed makes sense and is what I experienced with it. When you say for bounce shots and non perfect white ceilings are you talking about adding flash compensation or exposure compensation ?

[David Kilpatrick]

What I am saying is that the flash can run out of power entirely in larger, dark rooms with high ceilings - you can set f8, say, and think it may be OK, but even at f8 the flash will be at full power and will still be undexposing by 1/2 stop. If you get dark bounce shots, try doubling the ISO, then opening up the aperture.

David

[alphaman07]

David and fellow members of Photoclubalpha:

I believe I have reached closure in my search for understanding of the different ADI flash exposure characteristics between the Sony Alpha cameras and the Minolta Maxxum 7 camera. Yesterday in church I did a flash exposure comparison test using a friend's Nikon D300 with their SB-600 flash and my Alpha 700 with the Minolta 5600HS-D flash. Basically, with the same exposure parameters, both systems were equally fooled in classic flash exposure hazards, but I felt the A700 exposures were better! You can view the results of my test on this DPReview thread:

http://forums.dpreview.com/forums/read. ... e=29807751

The bottom line for me is that I need to accept the Alpha flash exposure system for what it is, there is nothing better elsewhere, and perhaps, the Alpha system offers more options for compensating. Therefore, in facing flash exposure hazards, I need to follow the advice of David and others and develop compensating techniques that suit my tastes. Finally I should remind all of David's excellent article on this site on flashes for the Sony Alpha cameras; it explains why ADI can't work the same on digital as it worked on film.

So friends, the Sony Alpha flash exposure system comes out in my estimation at least as good as anthing out there, and thus we can feel additional vindication as Alpha owners!

Fred from Pittsburgh, PA, USA